JPS5882649A - Operation of machine tool - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for operating a machine tool, and more particularly to a tool spindle having an axis of rotation, means for rotating the spindle by a predetermined angle of rotation, and moving transversely to said axis;
a table for changing its position relative to the spindle; a surface detection probe attached to the spindle; and means for transmitting a boop signal at the moment the probe reaches a detection position on the surface limited on the table; , a method for operating a machine tool having means fixed on a table for delivering a first signal in response to the generation of the probe signal, and a computer connected to introduce the output signal.

The above-mentioned four-piece is usually housed in a tool magazine. Its storage method is similar to that of rotary cutting tools used in machines. And when a measuring operation is required,
An automatic tool change mechanism mounts the probe on the spindle. This measuring operation is required before machining and determines the location of the surface to be machined. Alternatively, this measurement operation may be required after machining to inspect the dimensions of the machined surface.

The probe senses a surface at some distance from the spindle axis. This small distance is called a dip offset and is a value that must be taken into account during measurement operations. However, the offset (off-cella) is not constant in all directions of the spindle axis. This is partly due to the characteristics of the probe itself, and partly due to the unavoidable misalignment between the probe and the spindle.

Therefore, different offsets should be taken into account appropriately when measurements are subsequently taken on surfaces in different directions. If the spindle itself is not capable of rotation for the purpose of measuring surfaces in different directions, it may be necessary to offset the spindle scrap side in a particular direction when mounting the plate on the spindle. The probe needs to be calibrated for the sensing operation to be determined.

SUMMARY OF THE INVENTION In view of the above-mentioned points, it is an object of the present invention to provide a method by which the various offsets of the punches used in the machine tools described above can be automatically determined.

To achieve this objective, the present invention provides a test surface on the table or in a position adjacent to the workpiece, and operates the machine in a predetermined manner to measure the test surface, in which case the spindle is moved to the measuring surface. This includes an operation of rotating the probe by a necessary angle, and finally, calculations are performed using the measurement results to determine the probe offset.

Methods for determining only a single offset are already known. Therefore, when performing a measurement operation on a surface in a different direction, the spindle is rotated so that the offset is always perpendicular to the surface to be measured. This has the disadvantage of introducing inaccuracies, especially when measuring bores.

The present invention will be described in detail below with reference to the drawings.

Referring to FIG. 111 and FIG. 1, this machine tool is a machining center and consists of a fixed structure or base 10 and a support or table/l. This table l/ is adapted to support the workpiece lda at a predetermined reference position on the table // by means of a fixture lj. The machine has a tool support which is a spindle 16 supported on a base 10. This spindle l≦ is fixed by the stepper printer MX, and the axis l≦A
The object is rotated continuously around the axis and indexed between arbitrary angular positions around the axis. That Stetsu Binda Motor M! is a position sensor! and its sensor output terminal is connected to digital callan #lI. By supporting the table // on the pace 10 via the sliding device /1, it is directly moved in the x, Y and two directions of one orthogonal coordinate system. Its movement in each direction is driven by a motor.

and position sensor, vx, J
17Y and JZ allow continuous measurement of pace/θ. The outputs of these position sensors are output to digital counters 21X, 2/Y and J/Z. The output of each counter 1 is supplied to each comparator n (see No. 98). This comparator n is supplied with requested data from a register. A closed loop drives each motor M to the required position, and the difference between the contents of the associated counter l and register n is the error signal of such closed loop.

The machining unit 1tIJ No. has a reference pore 2-, and the reference point of the workpiece in the X direction and the Y direction is determined by three people on its axis.

The reference position of the workpiece l# on the table reference is set between the axis xA and the table reference #TX, TY, and TZ.
.

Defined by 10J and 10J. However, axis 1
The machining operation can be performed by a rotary cutting tool (not shown) that is concentric with the spindle l≦ and attached to the spindle l≦.
Moreover, since the measurement operation can be performed by the boop B (see Figs. 1 and 3) similarly attached to the spindle 16, the movement of the table for such an operation can be performed in relation to the axis /4A. Therefore, axis 76A becomes a fixed reference point, ie, a mechanical reference point. Therefore, the table reference surface T is initially installed on the fixture 11 only for operation, for example, only at the start of manufacturing operation. However, it is assumed that the counter l normally maintains zero on the reference plane T throughout the subsequent operation. To associate the review with axis 14, when counter l indicates that the workpiece is in the reference position,
It is necessary to arrange the housing appropriately so that A and 3A match. This does not necessarily occur in practice, and could probably be due to thermal contraction or expansion of the table, for example, between when the fixture was first installed and during subsequent production runs. obtain. Therefore, axis I may have a nominal reference position at which it coincides with axis 16 and causes axis S to offset from axis 14 in its actual reference position. ′
. The difference between these two reference positions is 1 work offset).
It is called.

The needle B has a bodice fixed to a spindle 14 (see Figure 1) and a needle 1 attached to the body 1 and having a bulbous end X. The probe B detects the work surface, that is, the surface of the workpiece, and in response to the engagement between the spherical surface l and the work surface, the probe B sends a step to the electric circuit 2 (see Figures 3 and 9 jl). Outputs signal III.

Connect the signal IJt so that counter 1 operates,
Thereby the instantaneous contents of that counter are stored in the respective register Jff.

j? Transfer to Y and gz. In this way, the position of the work surface is determined at the instant of transfer to register n or, in practice, at the instant of signal /II.

Assuming that the position of the work surface is related to the axis/4m,
The signal /Jt should occur when the machine plane intersects axis 14. This does not necessarily occur in practice, because the workpiece contact surface of sphere X is offset from axis 11 by the radius of the sphere, and another reason is that sphere Another reason is that the needle may be slightly bent before the signal X actually occurs. For these reasons, the work surface is
Signal /31 occurs when, for a plane, there is a relationship defined by the distance between axis 14 and the position of the work surface at the instant of signal /Jr. This distance is one response characteristic of the probe, or simply one probe offset.
It is called.

It should be clear that in order to measure any work surface, both work offset and probe offset should be considered. It is necessary to check these offsets from time to time, especially whenever a new workpiece is installed in the fixture.

The machine has a computer 100, which has a motor controller OO designed to move the motor in a predetermined sequence, thereby setting the water offset and the offset. Do it like this. Below is a list of parameters related to Punigeramuko OO.

Position signal or constant: 10/- Nominal X reference position of the axis (Figs. 1 and 2) Nominal Y reference position of the 10/- axis I (1st.
Figure) ioz-spherical end X (D nominal 2 reference position (
III/, J figure) 102--Angle position of spindle L (see figure) io≦-100 of spindle/4
Angular position (Reference, Figure 4.7) 107-Spindle l
1100 angular position of the spindle (Fig. 1) 2100 angular position of the spindle (Fig. 1) 109 - Reference bore diameter (Fig. J) These constants are stored in the computer's storage device and can be applied to any workpiece Applies to. The positions ioi, toco and 10J are immediately described. Positions IOj to lOl are shown in Figures 4 to 7.
As shown in the figure. These position signals are used to drive motor M through the aforementioned closed loop.

Trunk signal wealth ///- Signal that drives the motor ■ in the +X direction (Fig. 9) llJ- Signal that drives the motor in the -X direction -t
C89) llJ - Signal to drive the motor in the +Y direction (Figure 1) // Signal to drive the motor in the -Y direction (Figure D) 1J - Signal to move the motor forward //9 - Motor The signal drive signals for stepping the drive are output by the Pulgeramco OO to drive the motors M in an open-loop manner, which motors are stopped on the occurrence of the probe signal lJl. Driving the motor in the +X direction means that the table // moves in the -X direction, the axis /jA relatively moves in the +X direction, and so on.

External signal: /J/- position feedback from sensor I (see figure)
Position feedback from lλ sensor, VX (Figure D) / Position return M from λJ-sensor JY (Figure 9) / Position feedback from sensor JZ (Figure 9') / 12 register Position feedback from nX (Figure 9)/11-Position feedback from register JIY C89
Figure) lJt self-pre-prep signal The signal is read by the computer according to the request of program-〇〇.

Variable: Axis 11 indicated by M X/=corresponding counter/
The position in the X direction of the spindle is the position in the X direction where the 4-Pco is in contact with the surface area -DX of the borer, and the spindle l≦ is at the corner position 1.
0t s, that is, the value at the position of θ0 relative to λ (jth
vA).

Mu XJ = the position of axis 11 in the figure).

BX = X-direction position of axis/4A, the value when the probe is in contact with the surface -DX and the spindle 14 is in the angular position 104% or 90° (7th g4).

CXN=nominal position of the axis/4 mm in the X direction, in this example a value equal to the distance 10/ (FIG. 41).

CXA - Actual position of axis/AA in the X direction.

wox = value indicating the work offset in the x direction (Fig. 44) O POX / = value indicating the work offset in the +X direction .

POXJ = value C indicating the offset in the -X direction, ie the offset for measurements in the surface area -DX).

F is the diameter of the engineering standard borehole, and in this example, the value is 10/
(Figure 3).

Apart from the reference bore variable F, all the variables mentioned above relate to the X direction. Y-direction variables AX/, AYJ, BY, CYN, CYA corresponding to these values.

There are WOY, POY/ and POYJ. In this Y direction case, the variable WkAY/ is determined at the -07 surface of the /100 position of the spindle 14, and the variable BY
describes the quadrogram -00 in terms of the values determined at the zero angular position of the spindle /A. Here, it is assumed that one machining station is initially located at an arbitrary position away from the probe, and that the spindle/A is at an angular position of zero.

In steps JO7 to JO10, the signal 10/.

10J and 103t, respectively, to move the workpiece to the nominal reference position (411th
WJ). II indicates that the workpiece has reached the nominal reference position.
After II (step -〇-), register the signal toy! output and rotate the spindle/4rt core to the 00 position. After confirming that the spindle 16 has reached this 0° position (step o4I), the signal //J is output to drive the motor MXrt-X direction (step-○). In other words, the workpiece Move the surface region-DX toward the spherical end (No. [)].

The generation of the probe signal lJg is monitored by the step song, and when the probe signal /3t is generated (step 'l'
fJQ), outputs the signal //1 and stops driving the motor MX (step -〇g). After that, the signal -
The position of the workpiece at the moment when /31 occurs is in register JJ
It is read by reading the X signal 7.7J I (step code at). Finally, in this part of the program, the variable @AX/ is set to the value of signal 13 (step lo). Step Co// to Co J0
In order for the spindle 14 to rotate easily,
First move the workpiece to the nominal reference position (step co/
/), and the routine from steps J0J to J10 described above is repeated, except that the spindle /6 is rotated from /10° to the 90@ position (step CO/J). Thereafter, the workpiece is moved to engage portion 10DX of its surface with the Psepco (No. Am). Furthermore, measure the position of the axis/4 of the spindle when the probe signal lJ1 is generated due to such engagement (step 21D), and store the measured value as variable BX (step here O).
.

In step coco l or a core, step coco O
The same routine as J to -lQ is repeated, except in this case without rotating the spindle, i.e.
The surface region of the tt1 workpiece held at 0° position -DX is moved to engage the probe (step here), and the signal/
The measured position of axis 76 when 31 occurs is stored as variable @AX (step JJ).

In steps J, 7/ to -31, the variable AX/
.

Steps a, y3), and one probe offset P
Calculate OX/, POX. [lambda] (7 sets) is necessary because the response characteristics of the probe are usually not the same for both surface regions of the workpiece -DX and 10X.

Since the offsets of one spindle are usually different, rotating one spindle from the /10° position (step 13) requires calculating the work offset WOX (step JJ
, 7) is essential. The reason for this is that in calculating the work offset, it is necessary to accurately measure the middle 6 positions of the surface regions -DX and +DX of the workpiece. By rotating the spindle from the /10° position, the same 14-off offset is applied to the opposing surfaces -DX and +DX, giving the equation (AX/+AXJ
)/J ('XfTupkoJko) allows us to determine the exact center position between them. However, in order to determine the respective profiles, it is necessary to prevent the spindle from rotating and to engage the opposing sides of the spherical end with the opposing surfaces DX and DX. .

In the remainder of the graph (not shown), the workpiece returns to its nominal reference position. Then, in the step corresponding to step -0 IN 0t, the work offset and the A field offset in the Y direction are determined.

When the spindle axis moves in the X direction, the spherical thin part X does not actually move along the diameter of the bore in the X direction, but on a side path away from that diameter. It is necessary to pour in particular amounts. This results in errors due to the following reasons. That is, on the one hand, due to the distance between position M X/ and B, and on the other hand, due to the distance between position AX
This is due to the distance between / and the position. That distance is shorter than the distance that would occur if the spherical terminal were on a certain diameter. This difficulty is solved as follows: (i.e., one probe off)
After determining XJ, the computer is used to determine the position of the spindle axis, represented by 80x.

There, the average value of POX/ and POXJ lies on the T-axis of the bore, as shown.

Next, the spindle axis/1m moves to a position expressed by 80X=(AXJ+BX)/k. and work offset WoY and probe offset POY/.

POYJ is determined in the Y direction. In such a situation, it is preferable to first determine the probe offset without making any changes to the angular position of the spindle according to the equation shown below.

POYi=CF-(AYCOAY/))/KOPOYco=
AY co+POY/-F-BY spindle/4 tube Rotate tQ degrees to determine woytm.

That means that the position of the ball terminal in contact with the bore is the same as the position in which it was in contact with the bore when the spindle was in positions X/ and AX. Therefore, WOY can be determined in the same manner as when WOX was determined.

Finally, the spindle axis is 80Y=(AYJ+IIY)/
5. Repeat the pulses for determining POXl and POXJ to give accurate values. Its exact value can be obtained by moving the spindle axis in the X direction of the bore by the appropriate amount.

Value WOX, POX/, POXJ, WOY, POY/, P
OYJ.

After determining the SOx and goye as described above, the machine goes into measuring operation to determine the dimensions, i.e. the position of the workpiece in the X and Y directions. The relevant value is
is added to the positional dimension of the spindle 14 when the signal is generated.
Or subtracted from it.

The angular position used in his measurement operation is the position at which the spindle/meng has rotated 0 degrees.

This angular position will be held constant for all subsequent measurement operations.

The seal can be constructed as described in British Patent No. 1.41413.977, Nos. 1II to JrjlH.

[Brief explanation of the drawing]

1st w! J is a front view showing a configuration example of a machine tool to which the present invention is applied, FIG. 2 is a sectional view taken along line 1-1 in FIG.
gJ is a detailed enlarged view of the main part of Figure 1, the reference figure is a sectional view taken along the line WW@ in Figure 3, and Figures j to 1 are Figures 4I and 4I.
Explanatory drawing showing various operating positions of the detailed parts shown in the figure, No. 9
The figure is from TV! A block diagram showing an example of the configuration of the control circuit of the machine tool shown in J, and Figures 1O(2) to (B) are flowcharts showing examples of its operation. ...Workpiece, l3...Fixing tool, /4...Spindle, 16mm...Fixed shaft, /l...Sliding device, J5X, &Y, JZ, JI...Position sensor, ν
X, J/Y, Co/Z, 1/1... Digital counter, 1 dam... Reference bore, 1 dam... Axis, Co... 4-p, Mu... Body, Body...・Needle, C... Spherical end, MX, MY, MZ, M-% -#, TX, TY
, TZ-? -Pull reference plane, ioi~109...position signal or constant, ///N//de...drive signal, l/N/Jt...external signal, -〇〇...pu4gram, 201 ~23g...Psegram step, AX/, A
XJ, BX, CXN, CXA, WOX. WOY, POX/, POXJ, F, SOX, SOY...
・Variables, DX, DY...surface parts of the workpiece. Patent Applicant Renishi Sotsu Electrical Limited Drawing IP version (no change) hda 10(C) ~, 10(D) Procedural amendment December 14, 1981 Kazuo Wakasugi, Commissioner of the Patent Office 1. Indication of the case Japanese Patent Application No. 57-158782 2. Name of the invention Method of operating a machine tool 3. Person making the amendment Relationship with the case Patent applicant Renishaw Electrical Limited 4. Agent:
107 No. 405, Ice Annex Building 2, 6-9-5 Akasaka, Minato-ku, Tokyo 6, Subject of amendment Power of attorney (original and translation) 1 Drawing and priority certificate (original and translation) 7. Contents of amendment (1 ) As shown in the attached sheet (2) Engraving of drawings (no changes in content)

Claims (1)

[Claims] /) A tool spindle having a rotation axis, means for rotating the spindle by a predetermined angle, a table that moves across the axis and changes the position relative to the spindle, and the spindle. a surface sensing probe mounted on the table, means for generating a probe signal at the moment the probe reaches a detection position on the surface limited on the table, and means responsive to the generation of the probe signal; in operating a machine tool having means for transmitting an output corresponding to the position of an axis with respect to a reference fixed on the table, and a combiator connected to read the output; a first and a second test surface; a midpoint defining a first reference between the first and second test surfaces, where the midpoint is a request stored in the computer; The actual position C is separated from the position CN by an error component; Send out l, (electronic) rotate the spindle by 110 degrees,
d) moving the spindle so as to detect the first test surface and sending out a first output force corresponding to the output; (・) after step <a>, rotating the spindle once; Move the probe without causing the I
Detect the I/test surface, read the output from the computer written in (f) tlJ, perform the following calculation, and calculate WO-CN-(Ml+person-1)/PO/-(F-(AJ-A). /))/J *Yov, POJ
-AJ+PO/ -F-1 where, WOI, the above error, PO/ is the distance % between the spindle axis and the first test surface at the time of generation of the second output, POJ is the first output The distance between the spindle axis and the seventh test surface at the time when How to operate machine tools.